In general, a bill processing apparatus is incorporated into a service device such as a game medium rental machine installed in a game hall, a vending machine or a ticket-vending machine installed in a public space, or the like, which identifies the validity of a bill inserted from an insertion slot by a user and provides various types of products and services in accordance with a value of the bill having been judged as valid. Such a bill processing apparatus comprises a conveyance mechanism that conveys a bill inserted into an insertion slot, a bill identification part that conducts validity judgment whether the bill to be conveyed is valid or not, and a bill housing part (may also be referred to as a safe) that contains bills having been validated as are stacked sequentially after judging authenticity of the bills.
In the bill processing apparatus described above, after the bill is inserted from the insertion slot, it is necessary to prevent the inserted bill from being drawn out for the purpose of fraudulent activity. For example, a bill processing apparatus, which is provided with a shutter at an insertion slot such that it is prevented that a bill having been inserted through the insertion slot is drawn out by closing the insertion slot with the shutter after the insertion, is disclosed in Patent Document 1. In this bill processing apparatus, the bill inserted into the insertion slot is housed in a bill housing part after the bill is judged to be authentic. More specifically, a presser plate that is reciprocated as it passes through an opening is disposed inside the bill housing part, and a bill pushed by the presser plate passes through the opening as it bends flexibly and it is then loaded onto and housed at a predetermined position of the bill housing part.    Patent Document 1: Japanese patent No. 3000328